Hg vs hydrargyrum

Hg and hydrargyrum both are nouns.

Word	Noun	Adjective	Verb	Adverb
Hg	Yes	No	No	No
hydrargyrum	Yes	No	No	No

As nouns, Hg and hydrargyrum are synonyms defined as:

Hg and hydrargyrum: a heavy silvery toxic univalent and bivalent metallic element; the only metal that is liquid at ordinary temperatures

Other synonyms of Hg include atomic number 80, mercury, quicksilver.

Hg (noun)	hydrargyrum (noun)
a heavy silvery toxic univalent and bivalent metallic element; the only metal that is liquid at ordinary temperatures	a heavy silvery toxic univalent and bivalent metallic element; the only metal that is liquid at ordinary temperatures